Generally, a thumbnail image is implemented by displaying a specific frame of a moving picture to be smaller than its original size for summarizing, browsing, or searching a received or stored broadcast program. Namely, the thumbnail image provides implicative information to a user using a still image instead of a moving image. The thumbnail image enables to summarize contents of a video, which is received from a broadcasting station or recorded in a personal video recorder (PVR) of a digital TV, via several small pictures. And, the thumbnail image enables to generate a key frame for video indexing or a representative image for the purpose of a preview or digest for a program in a program guide. Hence, the thumbnail image is applicable to various fields of use.
Yet, the current system adopts a method of generating a thumbnail image via receiver such as DTV, set-top box, PVR, and the like instead of transmitting a thumbnail image from a broadcasting station. Hence, the receiver needs a separate thumbnail image generator to generate a thumbnail image.
A thumbnail image generator generally adopts a method of generating thumbnail image for the I-picture feasible for extraction of thumbnail image from an inputted video frame. This is to minimize hardware necessary for the thumbnail image generation using a DC value of the I-picture only.
However, in order to generate a thumbnail image enabling a user to clearly comprehend the meaning of program contents, the receiver substantially needs additional hardware and software. And, such an implementation needs high complexity and efficiency. Although the thumbnail image provides high quality of service to a user, the configuration of the receiver is considerably complicated as well as a price of the receiver is expensive.